Is the Azteca a tough place to play because it’s legitimately a tough place to play? Or is it known as a tough place to play because most of the teams that play there are CONCACAF teams that Mexico is, at worst, basically equal to in skill level? Wikipedia has results with a stadium listed going back to 2008 and they’ve played 6 teams outside our region there. Five of these were friendlies and one, against New Zealand in 2014 WC qualification, was a competitive match. Beat Chile 1-0 in 2010 and tied Spain the same year. Not sure the strength of Chile’s lineup but Spain half rotated their starters. Beat Israel and Scotland. Tied Portugal 0-0 earlier this year (Por made 9 subs in the game) and based on the stats, Por had the better of the play.
As for acclimating, how used to the altitude are the Mexico players? Of their starters against Ecuador, only 4 play at altitude for their clubs. Of their 23 outfield players on the roster, only 9 play at altitude.
I think this could come down to if Mexico is disciplined enough to set up and maintain a defensive block. Otherwise, England might be 3 goals up before they start to become affected by the altitude.